identify genetic modifiers of dermal neurofibroma burden, and 3) evaluate dermal neurofibromas and normal skin for the presence of targets of sorafenib. Successful validation of reliable quantitative imaging methods of dermal neurofibroma growth is a logical prerequisite to subsequent clinical trials with medical treatments, which will evaluate the effect of new agents on the growth rate of dermal neurofibromas. Identification of genetic modifiers may permit prediction of ultimate tumor burden. Evaluation of targets of new agents in dermal neurofibromas will allow for more rationale drug development for NF1. Given the paucity of protocols for adults with NF1 and dermal neurofibromas, this study will likely generate great interest among affected individuals and have rapid accrual.